1. Field of the Invention
The present invention relates to a machine for clearing land, and more particularly to an environment friendly attachment mounted on an excavator which grinds trees, shrubs, concrete, tree stumps and roots, and to a method of grinding standing large trees.
2. Description of the Related Art
In the past, land has been cleared for many purposes by removing tree stumps and tree roots. Large tractors have been used to remove tree stumps and roots from the ground. After removal from the ground, tree stumps and roots have been piled for burning, or they have been hauled away for disposal. Disposal at a remote location has been by burial, or by burning.
Environmental concerns, government requirements and cost have made it necessary to find other methods for clearing land. One method for land clearing is to grind tree stumps and roots into a mulch and leave the mulch in the ground where the tree stumps and roots were originally. This procedure eliminates transportation costs and disposal costs. Leaving such shredded wood and fiber mulch on the ground improves soil fertility.
Tree stump grinders have been used to grind tree stumps following the removal of a tree from areas near buildings or other areas where it is desirable to minimize disturbance of the surface.
Known stump machines generally comminute the portion of a stump that is above the ground and the portions which are near the surface. These stump grinding machines though do not operate on standing trees, only on stumps on which the majority of the standing tree portion has been previously removed. They grind up sufficient material to allow soil to cover the remaining stump and for grass to be planted. Such stump grinders generally do not remove all of a stump or tree roots. Stump grinders designed to grind the portion of a stump that is close to the surface are relatively slow. Additionally, such grinding machines have been oriented for horizontal rotation, not vertical rotation.